1. Field of the Invention
The present invention relates to a surgical instrument which is used when a surgical procedure, especially a surgical procedure that is performed under an endoscope, is performed by actuating a surgical treatment part disposed on the distal end portion of the insertion part of this instrument in a state in which an operating part disposed on the proximal end portion of this insertion part is gripped by the operator performing the surgical procedure.
2. Description of the Related Art
In the past, endoscopes which make it possible to perform various types of treatments on treatment sites while observing an object image with the endoscope (which has an insertion part formed as an elongated part) inserted into body cavities or the like have been widely used.
In recent years, furthermore, surgical procedures or the like in which therapeutic measures or treatments are performed under endoscopic observation without opening the abdomen have been performed in order to reduce the degree of invasion of a patient's body. In such surgical procedures, an endoscope used for observation is guided into a body cavity via a trocar, and a surgical instrument is guided to the treatment side inside the body cavity through this trocar. Then, a therapeutic procedure or treatment is performed while observing the surgical instrument and treatment site by means of the endoscope.
The surgical instrument that is used in surgical procedures or the like performed under an endoscope is long and slender, and is devised so that a surgical treatment part (hereafter also referred to as a “treatment member”) disposed on the distal end portion of the insertion part is actuated by operating an operating part disposed on the proximal end of the insertion part.
For example, instruments in which a treatment member disposed on the distal end is devised such that this treatment member can freely pivot with respect to the main axis of the surgical instrument and such that the treatment member that has thus been pivoted can be rotated about its own axis or the like are described in U.S. Pat. No. 5,374,277, U.S. Pat. No. 5,549,637 and U.S. Pat. No. 5,350,391.
In concrete terms, in the surgical instrument described in U.S. Pat. No. 5,374,277, the instrument comprises a pivoting joint that allows pivoting of the distal end portion with respect to the main axis of the surgical instrument, and comprises a mount for the treatment member on the distal end side of this pivoting joint. This mount has a construction which is divided by wrist means into a first mount on the distal end side and a second mount on the proximal end side. As a result, the treatment member disposed on the distal end portion of the first mount can be rotated about the axis on the distal end side of the pivoting joint.
The medical instrument described in U.S. Pat. No. 5,549,637 has a joint part. In this medical instrument, the distal end portion can pivot with respect to the main axis of the medical instrument, and can also rotate about the axis on the distal end side of the pivoting joint. Flexible driving means such as a wire, cable or the like are disposed in the pivoting mechanism of the distal end portion. Furthermore, spur gears or bevel gears are used in the respective parts of the operating part, pivoting joint part and the like as mechanisms for causing the rotation of the part on the distal end side of the pivoting joint about the axis. Moreover, a push rod form member is installed via a link part in the mechanism that operates the treatment member mounted on the distal end.
In the laparoscopic instrument described in U.S. Pat. No. 5,350,391, the pivoting operation of a treatment member installed on the distal end is performed by one handle of a pair of operating handles, and the operation of the opening-and-closing movement of this treatment member is performed by the other handle of this pair of operating handles.